
#include "md5.h"

#include <string.h>
#include "crypto-write.h"



void CMD5::MD5_Init()
{
    const uint32_t iv[_MD5_DIGEST_LENGTH] =
    {
        0x67452301,
        0xefcdab89,
        0x98badcfe,
        0x10325476,
    };
    memcpy(ctx_.state, iv, sizeof(ctx_.state));
    ctx_.count = 0;
    ctx_.index = 0;
}

#define COMPRESS(ctx, data) (_nettle_md5_compress((ctx)->state, (data)))

void CMD5::MD5_Update(size_t length, const uint8_t *data)
{
    MD_UPDATE(&ctx_, length, data, COMPRESS, ctx_.count++);
}

void CMD5::MD5_Final(uint8_t *digest)
{
    uint64_t bit_count;

    MD_PAD(&ctx_, 8, COMPRESS);

    /* There are 512 = 2^9 bits in one block */
    bit_count = (ctx_.count << 9) | (ctx_.index << 3);

    LE_WRITE_UINT64(ctx_.block + (MD5_BLOCK_SIZE - 8), bit_count);
    _nettle_md5_compress(ctx_.state, ctx_.block);

    _nettle_write_le32(OUTPUT_SIZE, digest, ctx_.state);
}

/* A block, treated as a sequence of 32-bit words. */
#define MD5_DATA_LENGTH 16

/* MD5 functions */

#define F1(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define F2(x, y, z) F1((z), (x), (y))
#define F3(x, y, z) ((x) ^ (y) ^ (z))
#define F4(x, y, z) ((y) ^ ((x) | ~(z)))

#define ROUND(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

void CMD5::_nettle_md5_compress(uint32_t *digest, const uint8_t *input)
{
    uint32_t data[MD5_DATA_LENGTH];
    uint32_t a, b, c, d;
    unsigned i;

    for (i = 0; i < MD5_DATA_LENGTH; i++, input += 4)
        data[i] = LE_READ_UINT32(input);

    a = digest[0];
    b = digest[1];
    c = digest[2];
    d = digest[3];

    ROUND(F1, a, b, c, d, data[0] + 0xd76aa478, 7);
    ROUND(F1, d, a, b, c, data[1] + 0xe8c7b756, 12);
    ROUND(F1, c, d, a, b, data[2] + 0x242070db, 17);
    ROUND(F1, b, c, d, a, data[3] + 0xc1bdceee, 22);
    ROUND(F1, a, b, c, d, data[4] + 0xf57c0faf, 7);
    ROUND(F1, d, a, b, c, data[5] + 0x4787c62a, 12);
    ROUND(F1, c, d, a, b, data[6] + 0xa8304613, 17);
    ROUND(F1, b, c, d, a, data[7] + 0xfd469501, 22);
    ROUND(F1, a, b, c, d, data[8] + 0x698098d8, 7);
    ROUND(F1, d, a, b, c, data[9] + 0x8b44f7af, 12);
    ROUND(F1, c, d, a, b, data[10] + 0xffff5bb1, 17);
    ROUND(F1, b, c, d, a, data[11] + 0x895cd7be, 22);
    ROUND(F1, a, b, c, d, data[12] + 0x6b901122, 7);
    ROUND(F1, d, a, b, c, data[13] + 0xfd987193, 12);
    ROUND(F1, c, d, a, b, data[14] + 0xa679438e, 17);
    ROUND(F1, b, c, d, a, data[15] + 0x49b40821, 22);

    ROUND(F2, a, b, c, d, data[1] + 0xf61e2562, 5);
    ROUND(F2, d, a, b, c, data[6] + 0xc040b340, 9);
    ROUND(F2, c, d, a, b, data[11] + 0x265e5a51, 14);
    ROUND(F2, b, c, d, a, data[0] + 0xe9b6c7aa, 20);
    ROUND(F2, a, b, c, d, data[5] + 0xd62f105d, 5);
    ROUND(F2, d, a, b, c, data[10] + 0x02441453, 9);
    ROUND(F2, c, d, a, b, data[15] + 0xd8a1e681, 14);
    ROUND(F2, b, c, d, a, data[4] + 0xe7d3fbc8, 20);
    ROUND(F2, a, b, c, d, data[9] + 0x21e1cde6, 5);
    ROUND(F2, d, a, b, c, data[14] + 0xc33707d6, 9);
    ROUND(F2, c, d, a, b, data[3] + 0xf4d50d87, 14);
    ROUND(F2, b, c, d, a, data[8] + 0x455a14ed, 20);
    ROUND(F2, a, b, c, d, data[13] + 0xa9e3e905, 5);
    ROUND(F2, d, a, b, c, data[2] + 0xfcefa3f8, 9);
    ROUND(F2, c, d, a, b, data[7] + 0x676f02d9, 14);
    ROUND(F2, b, c, d, a, data[12] + 0x8d2a4c8a, 20);

    ROUND(F3, a, b, c, d, data[5] + 0xfffa3942, 4);
    ROUND(F3, d, a, b, c, data[8] + 0x8771f681, 11);
    ROUND(F3, c, d, a, b, data[11] + 0x6d9d6122, 16);
    ROUND(F3, b, c, d, a, data[14] + 0xfde5380c, 23);
    ROUND(F3, a, b, c, d, data[1] + 0xa4beea44, 4);
    ROUND(F3, d, a, b, c, data[4] + 0x4bdecfa9, 11);
    ROUND(F3, c, d, a, b, data[7] + 0xf6bb4b60, 16);
    ROUND(F3, b, c, d, a, data[10] + 0xbebfbc70, 23);
    ROUND(F3, a, b, c, d, data[13] + 0x289b7ec6, 4);
    ROUND(F3, d, a, b, c, data[0] + 0xeaa127fa, 11);
    ROUND(F3, c, d, a, b, data[3] + 0xd4ef3085, 16);
    ROUND(F3, b, c, d, a, data[6] + 0x04881d05, 23);
    ROUND(F3, a, b, c, d, data[9] + 0xd9d4d039, 4);
    ROUND(F3, d, a, b, c, data[12] + 0xe6db99e5, 11);
    ROUND(F3, c, d, a, b, data[15] + 0x1fa27cf8, 16);
    ROUND(F3, b, c, d, a, data[2] + 0xc4ac5665, 23);

    ROUND(F4, a, b, c, d, data[0] + 0xf4292244, 6);
    ROUND(F4, d, a, b, c, data[7] + 0x432aff97, 10);
    ROUND(F4, c, d, a, b, data[14] + 0xab9423a7, 15);
    ROUND(F4, b, c, d, a, data[5] + 0xfc93a039, 21);
    ROUND(F4, a, b, c, d, data[12] + 0x655b59c3, 6);
    ROUND(F4, d, a, b, c, data[3] + 0x8f0ccc92, 10);
    ROUND(F4, c, d, a, b, data[10] + 0xffeff47d, 15);
    ROUND(F4, b, c, d, a, data[1] + 0x85845dd1, 21);
    ROUND(F4, a, b, c, d, data[8] + 0x6fa87e4f, 6);
    ROUND(F4, d, a, b, c, data[15] + 0xfe2ce6e0, 10);
    ROUND(F4, c, d, a, b, data[6] + 0xa3014314, 15);
    ROUND(F4, b, c, d, a, data[13] + 0x4e0811a1, 21);
    ROUND(F4, a, b, c, d, data[4] + 0xf7537e82, 6);
    ROUND(F4, d, a, b, c, data[11] + 0xbd3af235, 10);
    ROUND(F4, c, d, a, b, data[2] + 0x2ad7d2bb, 15);
    ROUND(F4, b, c, d, a, data[9] + 0xeb86d391, 21);

    digest[0] += a;
    digest[1] += b;
    digest[2] += c;
    digest[3] += d;
}

